#include "wm.h"

struct Payload
{
    Client            *client;
    struct wlr_output *output;
    struct timespec   *when;
    int x, y;
};

static
void
render(struct wlr_surface *surface, int sx, int sy, void *data)
{
    float matrix[9];
    double x, y;
    struct Payload *payload;

    struct wlr_box box;
    struct wlr_output *output;
    struct wlr_texture *texture;

    enum wl_output_transform transform;

    payload = data;
    output  = payload->output;

    texture = wlr_surface_get_texture(surface);
    if(!texture)
        return;

    x = 0, y = 0;
    wlr_output_layout_output_coords(server.monitor.layout, output, &x, &y);

    box = (struct wlr_box) {
        .x = x + payload->x + sx,
        .y = y + payload->y + sy,
        .width  = surface->current.width,
        .height = surface->current.height,
    };
    scale_box(&box, output->scale);

    transform = wlr_output_transform_invert(surface->current.transform);
    wlr_matrix_project_box(matrix, &box, transform, 0, output->transform_matrix);

    wlr_render_texture_with_matrix(server.renderer, texture, matrix, 1);
    wlr_surface_send_frame_done(surface, payload->when);
    wlr_presentation_surface_sampled_on_output(server.present, surface, output);
}

static
void
render_layer(struct wl_list *list, struct timespec *now)
{
    Layer *layer;
    wl_list_for_each(layer, list, link) {
        struct Payload payload= {
            .output = layer->surface->output,
            .x = layer->geometry.x,
            .y = layer->geometry.y,
            .when = now,
        };

        wlr_surface_for_each_surface(layer->surface->surface, render, &payload);
    }
}

static
void
render_clients(Monitor *monitor, struct timespec *now)
{
    double   x, y;
    int      i, w, h, bw;
    float    *color;

    Client  *client;
    struct wlr_output  *output;
    struct wlr_box     *borders;
    struct wlr_surface *surface;

    output = monitor->output;
    wl_list_for_each_reverse(client, &server.client.stack, stack) {
        if(!VISIBLE_ON(client, client->monitor))
            continue;
        if(!wlr_output_layout_intersects(server.monitor.layout, monitor->output, &client->geometry))
            continue;

        surface = client->xdg->surface;

        x = client->geometry.x, y = client->geometry.y;
        wlr_output_layout_output_coords(server.monitor.layout, output, &x, &y);

        if((bw=client->border)) {
            w = surface->current.width;
            h = surface->current.height;
            borders = (struct wlr_box[4]) {
                {x,      y,      w+2*bw, bw}, /* top */
                {x,      y+bw,   bw,     h},  /* left */
                {x+bw+w, y+bw,   bw,     h},  /* right */
                {x,      y+bw+h, w+2*bw, bw}, /* bottom */
            };

            color = (client == server.selected) ? cfg·focuscolor : cfg·bordercolor;
            for(i=0; i<4; i++) {
                scale_box(&borders[i], output->scale);
                wlr_render_rect(server.renderer, &borders[i], color, output->transform_matrix);
            }
        }

        struct Payload payload = {
            .output   = output,
            .when     = now,

            .x = client->geometry.x + client->border,
            .y = client->geometry.y + client->border,
        };

        wlr_xdg_surface_for_each_surface(client->xdg, render, &payload);
    }
}

void
render_monitor(struct wl_listener *l, void *data)
{
    int w, h;
    Client  *client;
    Monitor *monitor;
    struct timespec now;

    clock_gettime(CLOCK_MONOTONIC, &now);
    monitor = wl_container_of(l, monitor, event.render);

    wl_list_for_each(client, &server.client.list, link) {
        if(client->resize) {
            wlr_surface_send_frame_done(client->xdg->surface, &now);
        }
    }

    if(!wlr_output_attach_render(monitor->output, nil))
        return;

    wlr_output_effective_resolution(monitor->output, &w, &h);

    /* start of rendering kernel */
    wlr_renderer_begin(server.renderer, w, h);
    wlr_renderer_clear(server.renderer, cfg·rootcolor);

    render_layer(&monitor->layer[ZWLR_LAYER_SHELL_V1_LAYER_BACKGROUND], &now);
    render_layer(&monitor->layer[ZWLR_LAYER_SHELL_V1_LAYER_BOTTOM], &now);

    render_clients(monitor, &now);

    render_layer(&monitor->layer[ZWLR_LAYER_SHELL_V1_LAYER_TOP], &now);
    render_layer(&monitor->layer[ZWLR_LAYER_SHELL_V1_LAYER_OVERLAY], &now);

    wlr_output_render_software_cursors(monitor->output, nil);

    wlr_renderer_end(server.renderer);
    wlr_output_commit(monitor->output);
}